make CMake's version config file architecture-independent

CMakeLists.txt

@@ -89,8 +89,10 @@ endif()
 ## install header files, generate and install cmake config files for find_package()
 ##
 include(CMakePackageConfigHelpers)
-write_basic_package_version_file(
-    ${NLOHMANN_JSON_CMAKE_VERSION_CONFIG_FILE} COMPATIBILITY SameMajorVersion
+configure_file(
+    "cmake/nlohmann_jsonConfigVersion.cmake.in"
+    ${NLOHMANN_JSON_CMAKE_VERSION_CONFIG_FILE}
+    @ONLY
 )
 configure_file(
     ${NLOHMANN_JSON_CMAKE_CONFIG_TEMPLATE}

cmake/nlohmann_jsonConfigVersion.cmake.in

+set(PACKAGE_VERSION "@PROJECT_VERSION@")
+
+if(PACKAGE_VERSION VERSION_LESS PACKAGE_FIND_VERSION)
+  set(PACKAGE_VERSION_COMPATIBLE FALSE)
+else()
+
+  if(PACKAGE_FIND_VERSION_MAJOR STREQUAL "@PROJECT_VERSION_MAJOR@")
+    set(PACKAGE_VERSION_COMPATIBLE TRUE)
+  else()
+    set(PACKAGE_VERSION_COMPATIBLE FALSE)
+  endif()
+
+  if(PACKAGE_FIND_VERSION STREQUAL PACKAGE_VERSION)
+      set(PACKAGE_VERSION_EXACT TRUE)
+  endif()
+endif()